The present invention relates to a magnetic disk installed in a magnetic disk device, and more particularly, to a magnetic disk such as a discrete track medium and a patterned medium, and a manufacturing method thereof.
Recently, the attempt to introduce various types of technology has been made along with the trend of larger capacity and higher memory density of the magnetic disk device. For example, a magnetic disk such as a discrete track medium and a patterned medium has been proposed for enhancing the recording density. The magnetic disk device using the aforementioned magnetic disk has further reduced the distance between the magnetic head and the magnetic disk, which is as narrow as the value around 10 nm or less. Meanwhile, the reduced distance between the magnetic head and the magnetic disk is likely to cause the collision therebetween.
Japanese Unexamined Patent Application Publication No. 2006-147148 discloses the magnetic recording medium provided with plural recording tracks formed of the ferromagnetic members separately arranged on the soft magnetic layer on the non-magnetic substrate, each having a cross section protruding widthwise, and a carbon layer formed on the upper surface of the respective recording tracks and the soft magnetic layer between plural recording tracks such that the thickness of the carbon layer formed on the upper surface of the recording track is larger than that of the carbon layer formed on the soft magnetic layer between the plural recording tracks for forming the patterned medium with excellent durability capable of performing the high density recording.
Japanese Unexamined Patent Application Publication No. 5-258291 discloses the discrete disk having the sliding portion and the storage portion of the head and the disk separated, in which the hill-like structure serving as the separated bulkhead and the sliding portion is formed of the non-magnetic material with high wear resistance which is different from the material for forming the substrate so as to enhance the durability of the disk against the continuous sliding operations of the head and the disk.
As described in Japanese Unexamined Patent Application Publication No. 2006-147148, when the protrusion exists on the disk surface, and the head collides against the protrusion, the mechanical strength is deteriorated compared with the generally employed magnetic disk, for example, the recording film is likely to be peeled off or deformed owing to the sliding operation of the head.
As described in Japanese Unexamined Patent Application Publication No. 5-258291, when the hill portion is formed of the material with high wear resistance that is different from the one for forming the substrate, the durability of the portion on which the magnetic head slides becomes higher. As the number of interfaces between different materials increases, the rupture or the peeling occurs at the portion with weak strength of the interface between the different materials, that is, the hill-forming material and the material in contact with the hill. As a result, the hill collapses to cause the plastic deformation of the recording layer, thus erasing the magnetic record. Peeling of the interface between different materials causes corrosion of the magnetic disk.